Stability and Reactivity of Chemicals: Use of Interaction Matrix

During the hazard assessment of a chemical one must also scrutinize the stability of the substance and the possibility of hazardous reactions occurring under certain conditions. It is necessary to list the conditions which should be avoided, such as high or low temperatures, pressure, light and shock effects [Refs. 3, 8, and http://www.ilo.org],which may cause a dangerous reaction and if possible include a brief description of these.

As part of the assessment one also must identify the materials which may cause a dangerous reaction if they come into contact with the substance or preparation concerned, such as water, air, acids, bases,oxidizing agents, etc.  In addition it is necessary to list materials which may be produced in dangerous quantities upon decomposition. In a laboratory environment, the information pertaining to stability and reactivity of chemicals may be conveniently documented in the form of an “interaction matrix” [Ref. 2]which (for example) is illustrated in table 4.

Table 4 Interaction Matrix

As may be evident from fig 1, the interaction matrix essentially is a means to record the consequence of an accidental combination of the substances and / or conditions in the first column and the substances enlisted in the first row. The number of elements in the first row and the column may be expanded as a user may feel the need for. The user may then fill in the table (i.e, the individual boxes at the juncture of each row and column) with information on the expected consequences of each combination. Such a document may then become a source of information for decisions on expected experimental programs.